Compositions of matter and method of use to treat arthritic disease

ABSTRACT

This disclosure describes compositions of matter useful as anti-inflammatory agents and as inhibitors of the progressive joint deterioration characteristic of arthritic disease, and the methods of meliorating inflammation and of inhibiting joint deterioration in mammals therewith, the active ingredients of said compositions of matter being benzimidoylacetonitrile, meta-fluorobenzimidoylacetonitrile, para-fluorobenzimidoylacetonitrile, or mixtures thereof.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of my copending applicationSer. No. 814,604, filed July 11, 1977, now a bandoned, which in turn isa continuation-in-part of my abandoned application Ser. No. 757,280,filed Jan. 6, 1977 which in turn is a continuation-in-part of myabandoned application Ser. No. 664,470, filed Mar. 8, 1976 nowabandoned.

BRIEF SUMMARY OF THE INVENTION

This invention relates to novel compositions of matter useful asanti-inflammatory agents and as inhibitors of the progressive jointdeterioration characteristic of arthritic disease. More particularly, itrelates to therapeutic compositions containing benzimidoylacetonitrile,m-fluorobenzimidoylacetonitrile or p-fluorobenzimidoylacetonitrile (ormixtures thereof in any proportion) which meliorate inflammation andinhibit arthritic joint deterioration in mammals. The active ingredientsof the present invention and their tautomeric forms may be representedby the following structural formulae: ##STR1## wherein X is hydrogen,m-fluoro or p-fluoro. Benzimidoylacetonitrile andp-fluorobenzimidoylacetonitrile have been described by Lang et al., J.Med. Chem. 18, 441 (1975) and benzimidoylacetonitrile may be readilyprepared by the method of Iwai et al., Chem. Pharm. Bull. (Tokyo) 12,1446 (1964). This compound is also commercially available from theAldrich Chemical Co. of Milwaukee, Wisconsin, under the nameβ-iminohydrocinnamonitrile.

DETAILED DESCRIPTION OF THE INVENTION

Benzimidoylacetonitrile, m-fluorobenzimidoylacetonitrile andp-fluorobenzimidoylacetonitrile have been found to be highly useful formeliorating inflammation and inhibiting joint deterioration in mammalswhen administered in amounts ranging from about one milligram to about250 mg. per kilogram of body weight per day. A preferred dosage regimenfor optimum results would be from about 5 mg. to about 100 mg. perkilogram of body weight per day, and such dosage units are employed thata total of from about 0.35 gram to about 7.0 grams of the activeingredient for a subject of about 70 kg. of body weight are administeredin a 24 hour period. This dosage regimen may be adjusted to provide theoptimum therapeutic response. For example, several divided doses may beadministered daily or the dose may be proportionally reduced asindicated by the exigencies of the therapeutic situation. A decidedpractical advantage of this invention is that the active ingredients maybe administered in any convenient manner such as by the oral,intravenous, intramuscular, topical, intra-articular or subcutaneousroutes.

Compositions according to the present invention having the desiredclarity, stability and adaptability for parenteral and intra-articularuse are obtained by dissolving from 0.10% to 10.0% by weight of activecompound in a vehicle consisting of a polyhydric aliphatic alcohol ormixtures thereof. Especially satisfactory are glycerin, propyleneglycol, and polyethylene glycols. The polyethylene glycols consist of amixture of non-volatile, normally liquid, polyethylene glycols which aresoluble in both water and organic liquids and which have molecularweights of from about 200 to 1500. Although the amount of activecompound dissolved in the above vehicle may vary from 0.10 to 10.0% byweight, it is preferred that the amount of active compound employed byfrom about 3.0 to about 9.0% by weight. Although various mixtures of theaforementioned non-volatile polyethylene glycols may be employed, it ispreferred to use a mixture having an average molecular weight of fromabout 200 to about 400.

In addition to the active compounds, the parenteral solutions may alsocontain various preservatives which may be used to prevent bacterial andfungal contamination. The preservatives which may be used for thesepurposes are, for example, myristyl-gamma-picolinium chloride, phenylmercuric nitrate, benzalkonium chloride, phenethyl alcohol,p-chlorophenyl-α-glycerol ether, methyl and propyl parabens, andthimerosal. As a practical matter it is also convenient to employantioxidants. Suitable antioxidants include, for example, sodiumbisulfite, sodium metabisulfite, and sodium formaldehyde sulfoxylate.Generally, from about 0.05 to about 0.2% concentrations of antioxidantare employed.

For intramuscular injection, the preferred concentration of activecompound is 0.25 to 0.05 mg./ml. of the finished compositions. They areequally adapted to intravenous administration when diluted with water ordiluents employed in intravenous therapy such as isotonic glucose inappropriate quantities. For intravenous use, initial concentrations downto about 0.05 to 0.25 mg./ml. of active compound are satisfactory. Forintra-articular use for large joints such as the knee, from about two toabout 20 mg. per joint per week may be used, with proportionally smallerdoses for smaller joints.

The active compounds of the present invention may be orallyadministered, for example, with an inert diluent or with an assimilableedible carrier, or they may be enclosed in hard or soft shell gelatincapsules, or they may be compressed into tablets, or they may beincorporated directly with the food of the diet. For oral therapeuticadministration, the compounds may be incorporated with excipients andused in the form of tablets, troches, capsules, elixirs, suspensions,syrups, wafers, and the like. Such compositions and preparation shouldcontain at least 0.1% of active compound. The percentage of thecompositions and preparations may, of course, be varied and mayconveniently be between about 2% to about 60% of the weight of the unit.The amount of active ingredient in such therapeutically usefulcompositions is such that a suitable dosage will be obtained. Preferredcompositions or preparations according to the present invention areprepared so that an oral dosage unit form contains between about 50 and250 milligrams of active compound.

The tablets, troches, pills, capsules and the like may also contain thefollowing: a binder such as gum tragacanth, acacia, corn starch orgelatin; an excipient such as dicalcium phosphate; a disintegratingagent such as corn starch, potato starch, alginic acid and the like; alubricant such as magnesium stearate; and a sweetening agent such assucrose, lactose or saccharin may be added or a flavoring agent such aspeppermint, oil of wintergreen, or cherry flavoring. When the dosageunit form is a capsule, it may contain, in addition to materials of theabove type, a liquid carrier such as a fatty oil. Various othermaterials may be present as coatings or to otherwise modify the physicalform of the dosage unit. For instance, tablets, pills or capsules may becoated with shellac, sugar or both. A syrup or elixir may contain theactive compounds, sucrose as a sweetening agent, methyl andpropylparabens as preservatives, a dye and flavoring such as cherry ororange flavor. Of course, any material used in preparing any dosage unitform should be pharmaceutically pure and substantially non-toxic in theamounts employed.

In determining the acute anti-inflammatory activity ofbenzimidoylacetonitrile, Royal Hart, Wistar strain rats ranging inweight from 80 to 90 grams were used. The rats were fasted overnightprior to dosing but had free access to water. The compound wasadministered in aqueous suspension, by gavage, in a volume of 1.7 ml.per 50 grams of rat [corresponds by hydration volume used by Winter etal., Proc. Soc. Exp. Bio. & Med. 111, 544-547 (1962)]. The phlogisticagent used was carrageenin prepared as a sterile 1% suspension in 0.9%aqueous sodium chloride for routine testing. A volume of 0.05 ml. wasinjected through a 26 gauge needle into the planter tissue of the righthind paw. Measurements were made 5 hours after drug administration (4hours after carrageenin challenge). Volumes of both the normal andcarrageenin inflamed feet were determined. The difference between thetwo measurements is considered to be the increased edema due to thecarrageenin administration. Results are expressed as a C/T efficacyratio (edema of control animals/edema of treated animals) and C/T ratioof greater than 1.41% is considered as active. Table I records theresults of this test at the indicated dose levels ofbenzimidoylacetonitrile in comparison with known anti-inflammatoryagents.

                  TABLE I                                                         ______________________________________                                        The Effect of Anti-inflammatory Agents on                                     Carrageenin Induced Edema of the Rat Paw                                                 Dose                                                                          mg./kg.                                                                       of body                 C/T Edema                                  Compound   weight     No. of Rats  Ratio                                      ______________________________________                                        Controls   --         64           --                                         Benzimidoyl-                                                                             250         8           2.2                                        acetonitrile                                                                  Aspirin    250        32           2.8                                        Phenyl-    250        32           2.3                                        butazone                                                                      Indomethacin                                                                              25        32           2.9                                        ______________________________________                                    

The effect of benzimidoylacetonitrile on body temperature in yeastinduced pyrexia was determined by the following procedure. Groups ofthree Royal Hart, Wistar strain rats weighing 80±5 grams each wereinjected subcutaneously in the nape of the neck with 0.6 ml. of a 40%suspension of dried brewers yeast in distilled water. Test compoundswere suspended in a 1.5% buffered starch solution and administered at adose of 250 mg./kg., by gavage 17 hours after challenge. Control ratswere treated in a similar manner but received only the buffered starchsolution. At 19 hours post challenge the rectal temperature of each ratwas measured with an electric thermometer. Each dose response experimentwas replicated one or more times. Table II records the results of thistest comparing benzimidoylacetonitrile with known anti-inflammatoryagents.

                  TABLE II                                                        ______________________________________                                        The Effect of Test Drugs on the Body Temperature of                           Pyretic Rats                                                                              Dose   Rats With                                                              mg./kg.                                                                              Yeast Induced Pyresis                                                    of body           Decrease In                                   Compound      weight   Number   Body Temp. ° C.                        ______________________________________                                        Control       --       156      0                                             Benzimidoylacetoni-                                                                         250       6       1.4*                                          trile                                                                         Aspirin       250      15       1.5*                                          Phenylbutazone                                                                              250      15       1.5*                                          Indomethacin  250      21       2.5*                                          ______________________________________                                         *Significantly lower temperature than pyretic controls.                  

Adjuvant induced experimental polyarthritis is a specific systemicdisease of the rat which shares interesting similarities with rheumatoidarthritis. Specifically, the histology of the two diseases bears aremarkable resemblance as shown by C. M. Pearson et al., Am. J. Pathol.42, 73 (1963). E. M. Glenn, Am. J. Vet. Res. 27 (116), 339 (1966) hasclassified adjuvant induced polyarthritis as a crippling and permanentdeformity resulting from diffuse connective tissue involvement aroundcertain susceptible joints in the rat. Zahiri et al., Can. Med. Ass. J.101, 269 (1969) have shown that the fusiform swelling of the distaljoints is associated with edema, congestion and synovitis includingpannus formation, all of which precede the ultimate destruction of boneand cartilage. Furthermore, Zahiri et al. indicate that the cartilagedestruction in the joint is due to an invasive pannus which originatesin the marginal synovium and extends across the articular surface toerode it. When non-steroidal, anti-inflammatory agents such asindomethacin inhibit arthritic paw swelling, which is composed ofinflammatory cell infiltrates, they have also been shown to preventjoint and bone deterioration. See S. Wong et al., J. Pharm. & Exptl.Ther. 185, 127 (1973) and G. R. Bobalick et al., Agents & Actions 4, 364(1974). In a similar manner, inhibition of the progress of arthritis inpaws of rats treated with the compounds of this invention also lessensassociated joint deterioration.

The following test shows the activity of benzimidolylacetonitrile,m-fluorobenzimidoylacetonitrile and p-fluorobenzimidoylacetonitrileagainst chronic inflammation in adjuvent induced arthritis which isaccompanied by joint destruction. Groups of three Royal Hart, Wistarstrain rats weighing 200±10 grams each were injected intradermally in inthe right hind paw with Freund's adjuvant (dried human tubercle bacilliin a mineral oil vehicle) at a dose of 2 mg./kg. of body weight. Testcompounds were administered orally in a 1.5% staruh vehicle at variousdoses once daily on days 0 through 13 post challenge. Control rats weretreated in a similar manner, but given only starch vehicle. On the 14thand 21st day post challenge the diameter of the injected paw (primarylesion) was measured by micrometer caliper. The volume of inflamed pawswere estimated from these measurements and the results are expressed aspercent inhibition of swelling as compared to controls. At the sametime, the other inflamed sites, such as ears, paws and tail (secondarylesions) were observed and each rat was graded as to degree ofinflammation and swelling present. The grading is based on a scale of 0to 24, where 0 represents a complete absence of induced arthriticnodules and 24 represents the maximum degree of inflammation. The meangrade for each treated group is calculated and the effects of eachcompound are expressed as percent inhibition of the control grade. TableIII records the results of these tests conducted withbenzimidoylacetonitrile, m-fluorobenzimidoylacetonitrile andp-fluorobenzimidoylacetonitrile and known anti-inflammatory agents. Theactive compounds of the present invention suppress the progression ofthe arthritis and associated joint deterioration. Of particular interestis the low mortality observed with benzimidoylacetonitrile treated ratsrelative to either controls or rats treated with standard compounds.Benzimidoylacetonitrile also appears to have a longer duration of actionthan standards as shown by the greater suppression of primary andsecondary lesions at the 21 day observation period.

                                      TABLE III                                   __________________________________________________________________________    The Effect of Anti-inflammatory Agents on Adjuvant Arthritis in Rats                 Oral               % Inhibition                                                                           % Inhibition of                                   Dose        Mean Weight                                                                          of Swelling                                                                            Control Grade                                     mg./kg.     Gain (grams)                                                                         (primary lesion)                                                                       (secondary lesion)                                of body                                                                            Dead/Treated                                                                         Day Day                                                                              Day   Day                                                                              Day    Day                                 Compound                                                                             weight                                                                             At 21 Days                                                                           14  21 14    21 14     21                                  __________________________________________________________________________    Normal Rats                                                                          --   8/186  77  112                                                                              --    -- --     --                                  Adjuvant                                                                      Controls                                                                             --   53/630 36  31  0     0  0      0                                  Indomethacin                                                                         2    8/57   68* 68*                                                                              51*   24*                                                                              38*    25*                                        1    9/54   63* 65*                                                                              46*   19*                                                                              34*    20*                                        0.5  5/54   53* 51*                                                                              40*   20*                                                                              25*    17*                                        0.25 0/9    51  57*                                                                              30*    4 22*     4                                  Aspirin                                                                              400  19/57  41  55*                                                                              73*   48*                                                                              58*    45*                                        200  10/66  40  44 48*   27*                                                                              26*    17*                                        100  18/63  48  53*                                                                              36*   13 19*     8                                         50   2/21   56* 44 23*    3 12      9                                  Phenylbuta-                                                                          150  2/27   40  50*                                                                              75*   44*                                                                              54*    31*                                 zone   75   2/39   51* 50*                                                                              62*   28*                                                                              27*    15                                         37.5 5/39   53* 53*                                                                              56*   14 18     13                                         18.8 2/21   50* 45 31    7  4      8                                   Benzimidoyl-                                                                         100  0/15   46  65*                                                                              68*   60*                                                                              57*    46*                                 acetonitrile                                                                         50   1/24   31  49*                                                                              63*   62*                                                                              59*    48*                                        25   1/9    41  38 33*   32*                                                                              33*    16*                                 P-Fluorobenz-                                                                        100  1/18   78* 67*                                                                              53*   29*                                                                              49*    22*                                 imidolaceto-                                                                         50   4/36   66* 57*                                                                              43*   25*                                                                              27*    8                                   nitrile                                                                              25   2/18   53  50 26    14 14     9                                   m-Fluorobenz-                                                                        50   1/18   64  60 40*   7  --     --                                  imidolylaceto-                                                                nitrile                                                                       __________________________________________________________________________     *Significantly different from adjuvant controls.                         

Another method of determining a drug effect on conditions which resultin inflammation is by measuring the effect on ultraviolet inducederythema in guinea pigs. Albino guinea pigs were depilitated on theirflanks, the evening before testing, with a standard mixture of bariumsulfide and gum acacia. On the morning of the test at 0 hour they wererestrained in a plastic container which allows exposure of 3 circularspots. They were then exposed to ultraviolet irradiation from a"Hanovia" Kromayer lamp, model 10, for 60 seconds. Immediately afterexposure to ultraviolet light, the guinea pigs were treated bydissolving the test compound in ethyl alcohol at various concentrationsand swabbing the UV exposed areas with the aid of a cotton tippedapplicator stick. At one and four hours, the degree of erythema for eachof the three sites was assessed according to the following scoringsystem: 0 = no erythema, 0.5 = incomplete circle or faint erythema and1.0 = complete circle of distinct erythema. Thus, the maximum score foreach animal was 3.0. The following Table IV summarizes the results ofthis test with benzimidoylacetonitrile and other drugs known to have abeneficial effect in erythema in warm-blooded animals.

                                      TABLE IV                                    __________________________________________________________________________    The Comparative Effect of Topically Applied Anti-inflammatory                 Agents on Development of Erythema in Guinea Pigs (pooled data)                Vehicle For Topical     % Concentration                                                                         Number of                                                                           Score (Avg.)                          Application                                                                              Drug         of Drug In Vehicle                                                                      Animals                                                                             1 Hr.                                                                             4 Hr.                             __________________________________________________________________________    Ethyl Alcohol                                                                            Control      --        40    2.5 3.0                                          Indomethacin 1         16    0.7*                                                                              2.5                                                       0.5       8     1.5 2.4                                                       0.25      8     1.8 2.5                                          Aspirin      1         4     1.9 2.8                                          Phenylbutazone                                                                             1         8     0.5*                                                                              2.4                                          Benzimidoylacetonitrile                                                                    2         8     0.6*                                                                              2.7                                                       1         4     1.0 2.8                               __________________________________________________________________________     *Statistically significant activity.                                     

The invention will be described in greater detail in conjunction withthe following specific examples.

EXAMPLE 1

    ______________________________________                                        Preparation of 50 mg. Tablets                                                 Per Tablet                Per 10,000 Tablets                                  ______________________________________                                        0.050 gm.                                                                             Benzimidoylacetonitrile                                                                         500 gm.                                             0.080 gm.                                                                             Lactose           800 gm.                                             0.010 gm.                                                                             Corn Starch (for mix)                                                                           100 gm.                                             0.008 gm.                                                                             Corn Starch (for paste)                                                                          75 gm.                                             0.148 gm.                 1475 gm                                             0.002 gm.                                                                             Magnesium Stearate (1%)                                                                          15 gm.                                             0.150 gm.                 1490 gm.                                            ______________________________________                                    

The benzimidoylacetonitrile, lactose and corn starch (for mix) areblended together. The corn starch (for paste) is suspended in 600 ml. ofwater and heated with stirring to form a paste. This paste is then usedto granulate the mixed powders. Additional water is used if necessary.The wet granules are passed through a No. 8 hand screen and dried at120° F. The dry granules are then passed through a No. 16 screen. Themixture is lubricated with 1% magnesium stearate and compressed intotablets in a suitable tableting machine.

EXAMPLE 2

    ______________________________________                                        Preparation of Oral Syrup                                                     Ingredient                Amount                                              ______________________________________                                        p-Fluorobenzimidoylacetonitrile                                                                         500 mg.                                             Sorbito Solution (70% N.F.)                                                                              40 ml.                                             Sodium benzoate           150 mg.                                             Saccharin                  10 mg.                                             Red dye                    10 mg.                                             Cherry flavor              50 mg.                                             Distilled water qs ad     100 mg.                                             ______________________________________                                    

The sorbitol solution is added to 40 ml. of distilled water and thep-fluorobenzimidoylacetonitrile is suspended therein. The saccharin,sodium benzoate, flavor and dye are added and dissolved. The volume isadjusted to 100 ml. with distilled water. Each ml. of syrup contains 5mg. of p-fluorobenzimidoylacetonitrile.

EXAMPLE 3 Preparation of Parenteral Solution

In a solution of 700 ml. of propylene glycol and 200 ml. of water forinjection is suspended 20.0 grams of benzimidoylacetonitrile withstirring. After suspension is complete, the pH is adjusted to 5.5 withhydrochloric acid and the volume is made up to 1000 ml. with water forinjection. The formulation is sterilized, filled into 5.0 ml. ampouleseach containing 2.0 ml. (representing 40 mg. of drug) and sealed undernitrogen.

EXAMPLE 4

    ______________________________________                                        Preparation of Topical Cream                                                  Ingredient                Amount                                              ______________________________________                                        m-Fluorobenzimidoylacetonitrile                                                                         1.0%                                                Ethoxylated stearyl alcohol                                                                             10.0%                                               Benzyl alcohol            0.9%                                                Isopropyl palmitate       5.0%                                                Glycerin                  5.0%                                                Sorbitol solution (USP)   5.0%                                                Lactic acid qs. to ph 4.0-5.0                                                 Water qs. to              100.0%                                              ______________________________________                                    

The ethoxylated stearyl alcohol and isopropyl palmitate are heated toliquifying temperature. About 95% of the total volume of water is placedin a separate container followed by the glycerin and sorbitol solution.This aqueous mixture is brought to a boil and then cooled to 60°-75° C.The m-fluorobenzimidoylacetonitrile is added to the wax phase and themixture is stirred until a clear solution is obtained. The benzylalcohol is added and dissolved in the wax phase while maintainingagitation. Both phases are kept at about the same temperature duringtransfer. The mixture is cooled while agitation is continued. At atemperature of 50°-55° C. the balance of the water is added. The pH isadjusted to 4.0-5.0 with lactic acid. The batch is cooled with minimumagitation until the cream sets in its final form.

EXAMPLE 5

    ______________________________________                                        Preparation of Intra-articular Product                                        Ingredient               Amount                                               ______________________________________                                        Benzimidoylacetonitrile  2-20 mg.                                             NaCl (physiological saline)                                                                            0.9%                                                 Benzyl alcohol N.F.      0.9%                                                 Sodium carboxymethylcellulose                                                                          1-5%                                                 pH adjusted to 5.0-7.5                                                        Water for injection qs ad                                                                              100%                                                 ______________________________________                                    

EXAMPLE 6

    ______________________________________                                        Preparation of Injectable Depo Suspension                                     Ingredient               % W/V                                                ______________________________________                                        Benzimidoylacetonitrile  0.05-5.0                                             Polysorbate 80 USP       0.2                                                  Polyethylene glycol 4000 USP                                                                           3.0                                                  Sodium chloride USP      0.8                                                  Benzyl alcohol N.F.      0.9                                                  HCl to pH 6-8            qs                                                   Water for injection qs ad                                                                              100.0                                                ______________________________________                                    

EXAMPLE 7 Preparation of m-Fluorobenzimidoylacetonitrile

A 1.21 g. portion of m-fluorobenzonitrile, 0.52 ml. of acetonitrile, 0.5g. of sodium hydride and 0.1 ml. of t-butanol are added to 25 ml. ofether. The mixture is refluxed on a steam bath for one hour. Methanoland water are added. The layers are separated and the aqueous layer isextracted with two 25 ml. portions of ether. The combined ether layersare dried over sodium sulfate, passed through diatomaceous earth,diluted with hexanes and evaporated on a steam bath. The resulting oilis chromatographed using methylene chloride on silica gel giving 0.52 g.of an oil which crystallizes. This material is taken up in methylenechloride. Hexanes are added and the mixture is evaporated giving an oilwhich crystallizes. This material is recrystallized from carbontetrachloride giving the desired product, m.p. 67°-68° C.

I claim:
 1. The method of inhibiting the progression of arthritis in amammal which comprises administering to said mammal an effective amountof an active ingredient selected from the group consisting ofbenzimidoylacetonitrile, p-fluorobenzimidoylacetonitrile and mixturesthereof.
 2. The method of inhibiting progressive joint deterioration ina mammal which comprises administering to said mammal an effectiveamount of an active ingredient selected from the group consisting ofbenzimidoylacetonitrile, p-fluorobenzimidoylacetonitrile and mixturesthereof.
 3. The method of meliorating inflammation in a mammal whichcomprises administering to said mammal an effective amount of an activeingredient selected from the group consisting ofbenzimidoylacetonitrile, p-fluorobenzimidoylacetonitrile and mixturesthereof.
 4. An anti-arthritic composition in dosage unit form useful formeliorating the inflammation and/or the progressive joint deteriorationcharacteristic of arthritic disease in mammals comprising from about onemilligram to about 250 milligrams per kilogram of body weight per dosageunit of an active ingredient selected from the group consisting ofbenzimidoylacetonitrile, p-fluorobenzimidoylacetonitrile and mixturesthereof, in association with pharmaceutical carrier.
 5. The compositionin accordance with claim 4 wherein the active ingredient isbenzimidoylacetonitrile.
 6. The composition in accordance with claim 4wherein the active ingredient is p-fluorobenzimidoylacetonitrile.